Update some obsolete references

Some links were still pointing to `/keyboards/ergodox_ez`, while the
directory is `/keyboards/erdogox` now.

Not all references have been updated, and some of the text here and
there may need updating to mention the ErgoDox Infinity too, but that's
out of the scope for this quick fix.

Signed-off-by: Gergely Nagy <[email protected]>

keyboards/ergodox/keymaps/supercoder/readme.md

@@ -23,7 +23,7 @@ your own:
 
 ```
 $ git clone https://github.com/jackhumbert/qmk_firmware.git
-$ cd qmk_firmware/keyboards/ergodox_ez
+$ cd qmk_firmware/keyboards/ergodox
 $ git clone https://github.com/algernon/ergodox-supercoder.git keymaps/supercoder
 $ make KEYMAP=supercoder
 ```